1. Field of the invention
This invention relates to a method for the formation of images, using a photoconductive toner.
2. Description of the prior art
A method using a photoconductive toner has been used for drawing lines in the production process of ships and for photo-electrophoresis. In recent years, an inky film made from photoconductive particles or toners has been proposed as a printer. It suggests that photoconductive toners can be used as a material for the formation of images.
A photoconductive toner used for the xerographic method, in which the photoconductive toner is coated on a substrate and then successively subjected to a charging step, an exposure step and an electrostatical transferring step, has insufficient capacity for holding electric charges thereon, so that the surface potential of the charged toner layer is remarkably low. Moreover, all of the electrical charges on the toner layer are not necessarily discharged in the exposure step, but a portion of them still remain as residual charges, so that the difference between the amount of charges in the exposed area and the nonexposed area on the toner layer must be small, resulting in an indistinct electrostatic latent image on the toner, which causes an indistinct final image on the transfer paper and also an increase in the fog density of the final image. In order to eliminate the residual charges and increase the initial surface potential to improve the distinction of the electrostatic latent image, improvements in the toner materials and system have been proposed. However, they cannot eliminate the above-mentioned drawbacks of the prior art because the fundamental characteristics (e.g., charging characteristics and spectral sensitivities) of the photoconductive toner and/or the photoconductive toner layer have not yet been sufficiently analyzed.